Question

big ideas

• through the movement of crustal plates, earth and its ocean have changed over time.
• the theory of plate tectonics explains how geologic features on earths surface and seafloor were created and how they have changed.
• this theory illustrates the nature of science, in which hypotheses are formed, data are collected and ideas are re - examined over time as new evidence becomes available.

engage
in this lesson you will learn about plate tectonics and how features of the seafloor were formed. use the chart below to record what you already know about these topics. after you complete the lesson, use the chart to record new information you learned.
before reading and trying the activities in your textbook, think about the questions below. record what you know about each topic in the what i know column of the chart.
question|what i know|what i learned
have the continents always had their current shape and configuration?
how do the continents move?
how are features of the seafloor, such as trenches, ridges and abyssal plains formed?
what are scientific theories?

Explanation:

The questions pertain to Earth - related phenomena such as continental movement and seafloor feature formation, which are explained by the theory of plate tectonics. Scientific theories in general are also a topic. These are key concepts in the study of Earth's physical features and processes.

Answer:

• Have the continents always had their current shape and configuration? No, the continents have changed over time due to the movement of tectonic plates.
• How do the continents move? Continents move as part of tectonic plates that glide over the semi - molten asthenosphere below the Earth's crust.
• How are features of the seafloor, such as trenches, ridges and abyssal plains formed? Trenches form at subduction zones where one plate is forced under another, ridges are created at divergent plate boundaries where new crust is formed, and abyssal plains are flat areas of the ocean floor formed by sediment deposition.
• What are scientific theories? Scientific theories are well - substantiated explanations of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experimentation.